Feed it through the antenna jack. Attaching the wire directly to the whip will cause overload with many portable receivers. Most antenna jacks feed into an attenuating circuit in the radio that's there to prevent overload.
If you're in a very noisy area,here's a quick and dirty trick. Forget stringing wires from trees,lay the wire directly on the ground. It cuts the noise significantly. During the summer on some HF bands,it's the only way I can hear anything other than the powerhouses able overcome the noise. You can use more wire too,if the ground attenuates the signals too greatly.
If you're looking for a good used tabletop receiver, the Drake R-4 is hard to beat. Yeah,it's nearly 50 years old,but they're a helluva radio,and you can pick 'em up at hamfests for under 200 bucks. The things are built like tanks.